SCF Reference Manual for the Storage Subsystem (G06.24+, H06.03+)

Configuring Magnetic Disks
SCF Reference Manual for the Storage Subsystem—529937-007
6-25
Configuring the Size of Disk Cache
3. Save accumulated statistical data before flushing it:
-> STATS / OUT STATSLOG / $DATA10
4. For an explanation of the display fields and for help determining if memory
allocation is adequate, see Displaying Disk Cache Configuration Information on
page 5-14
5. Change the 4K cache block size to increase the number of blocks allocated to
2000:
-> ALTER $DATA10, CACHE ( 4K, 2000 )
6. View the new cache configuration information:
-> INFO $DATA10, CACHE
7. Reset all counters for the disk:
-> STATS $DATA10, RESET
Resetting the statistics after a cache configuration change lets you see how the
new values affect performance. For more information, see Reconfiguring Cache to
Resolve Performance Problems on page 5-17.
STORAGE - Stats DISK \COMM.$DATA10
Current Time............. 18 May 2001, 11:34:27.606
Counters Reset Time...... 17 Feb 2001, 12:37:32.929
Elapsed Time............. 89 days, 22:56:54
Bytes Allocated To Cache. 4608 KB
Writes/Control Point..... 0.00
Cache Block Size_________________512_________1024_________2048_________4096__
Blocks Requested......... -1 -1 -1 -1
Blocks Allocated......... 160 144 144 1024
Blocks In Use............ 0 1 0 3
Blocks Dirty............. 0 % 0 % 0 % 0 %
Cache Reads.............. 0 % 0 % 0 % 18 %
Cache Read Hits.......... 0 % 0 % 0 % 99 %
Cache Read Misses........ 0 % 0 % 0 % 1 %
Cache Writes............. 0 % 100 % 0 % 82 %
Cache Write Dirties...... 0 % 0 % 0 % 0 %
Cache Write Cleans....... 0 % 100 % 0 % 99 %
Cache Write Misses....... 0 % 0 % 0 % 1 %
Cache Calls.............. 0 20 0 497234
Cache Faults............. 0 0 0 0
Audit Forces............. 0 0 0 0
STORAGE - Cache Information Magnetic DISK \COMM.$DATA10
Cache Block Size ________________512_________1024_________2048_________4096_
*Blocks Requested: -1 -1 -1 2000
Blocks Allocated: 160 144 144 2000
Bytes Allocated To Cache: 8512 K